1. Field of the Invention
The present invention relates to a webbing retractor which forms a seat belt device of a vehicle, and to a method of assembling a webbing retractor for assembling this type of webbing retractor.
2. Description of the Related Art
One longitudinal direction end portion of a webbing belt, which forms a seat belt device for restraining the body of a vehicle occupant seated in a seat of a vehicle, is anchored on the take-up shaft of a webbing retractor which is provided, for example, at the side of the seat. The other end of the webbing belt is fixed at an anchor plate provided in a vicinity of the webbing retractor. Above the retractor, e.g., at the upper end of the center pillar of the vehicle, the intermediate portion in the longitudinal direction of the webbing belt is passed through an insert-through hole formed in a through-anchor, and is folded back downwardly.
The portion of the webbing belt between the other end thereof and the folded-back portion thereof at the through-anchor passes through an insert-through hole of a tongue plate. By pulling the tongue plate, the webbing belt, which is taken-up on the take-up shaft of the retractor, is pulled out. Then, when the tongue plate is connected to a buckle device provided at the side of the seat opposite the side at which the retractor is provided, the webbing belt is set in a state of being applied to the vehicle occupant.
In a webbing retractor such as that described above, a supporting member, which is made of resin and is mounted to a power spring which urges the take-up shaft, and a gear, which is made of resin and which forms a lock mechanism which restricts rotation of the take-up shaft in the direction of pulling out the webbing belt when the vehicle is in a state of rapid deceleration, are mounted to the axial direction ends of the take-up shaft. The supporting member and the gear and the like are supported via other members at a pair of leg plates forming a frame. The take-up shaft is thereby shaft-supported at the frame so as to be freely rotatable.
When the take-up shaft rotates, and in particular, when the take-up shaft rotates due to the webbing belt being pulled-out suddenly, there are cases in which the take-up shaft does not only rotate around the axial center thereof, but also attempts to shift along the axial direction thereof.
As described above, resin members are mounted to the both ends of the take-up shaft. Because the take-up shaft is supported via these resin members, when the take-up shaft attempts to shift in the axial direction thereof due to excessive force, the force thereof is applied to the resin members.
Depending on the type of the webbing retractor, there are cases in which a take-up shaft, whose entire length along the axial direction thereof is longer than the interval between the pair of leg plates, is used.
In this type of webbing retractor, it has been thought to pass the take-up shaft through ratchet holes of the leg plates, which ratchet holes form the aforementioned lock mechanism, so as to dispose the take-up shaft at a predetermined position with respect to the pair of leg plates.
However, when shifting (displacement) of the take-up shaft in the axial direction such as described above arises, the take-up shaft attempts to come out from the ratchet holes. Therefore, the assembly process of simply passing the take-up shaft through the ratchet holes of the leg plates and disposing the take-up shaft at a predetermined position with respect to the pair of leg plates, is difficult. As a result, the bothersome assembly process of mounting the take-up shaft to the frame while moving the take-up shaft complexly and in three dimensions, has been carried out.
In view of the aforementioned, an object of the present invention is to provide a webbing retractor and a method of assembling the webbing retractor in which displacement (shifting) in the axial direction of a take-up shaft with respect to a frame can be restricted with a simple structure, and assembly of the take-up shaft to the frame is made easy.
A webbing retractor of a first aspect of the present invention has a take-up shaft, a frame, and a take-up shaft stopper device. The take-up shaft is a member on which the proximal end portion of an elongated, strip-shaped webbing belt is anchored, and which takes up the webbing belt from the proximal end side thereof by rotating in a take-up direction which is one direction around an axial center of the take-up shaft. The frame is a member having a pair of leg plates which oppose one another along an axial direction of the take-up shaft, and which indirectly supports the take-up shaft at the leg plates. The take-up shaft stopper device is a member which is mounted to one portion of an outer periphery of the take-up shaft from a direction orthogonal to the axial direction of the take-up shaft. The take-up shaft stopper device has a restricting wall. In the state in which the take-up shaft stopper device is mounted, the restricting wall extends further than the take-up shaft in the direction orthogonal to the axial direction of the take-up shaft, and opposes the leg plates along the axial direction of the take-up shaft.
In the webbing retractor having the above-described structure, the proximal end portion of the elongated, strip-shaped webbing belt is anchored on the take-up shaft which is indirectly supported at the pair of leg plates of the frame. Due to the take-up shaft rotating in the take-up direction which is one direction around the axis thereof, the webbing belt is taken-up onto and accommodated on the take-up shaft.
In this accommodated state, by rotating the take-up shaft in the pull-out direction which is opposite to the take-up direction by pulling the distal end side of the webbing belt, the webbing belt which is taken-up on the take-up shaft is pulled out. Due to a vehicle occupant making the webbing belt, which has been pulled out, span across his/her body at the front side of his/her body, the webbing belt is applied to the body of the vehicle occupant.
In cases such as those described above in which the webbing belt is taken-up on the take-up shaft and accommodated, or the webbing belt which has been taken up on the take-up shaft is pulled out, or the like, when the take-up shaft is rotated, the rotational force is applied not only in the direction around the axis of the take-up shaft, but also in the axial direction of the take-up shaft, and the take-up shaft attempts to shift in the axial direction thereof with respect to the frame.
In the present webbing retractor, the restricting wall of the take-up shaft stopper device, which is mounted to one portion of the outer periphery of the take-up shaft, extends further outwardly than the take-up shaft in the direction orthogonal to the axis of the take-up shaft. The restricting wall opposes the pair of leg plates along the axial direction of the take-up shaft. Thus, when the take-up shaft attempts to shift in the axial direction, the leg plates interfere, via the restricting wall, with the take-up shaft to which the take-up shaft stopper device is mounted. In this way, displacement of the take-up shaft along the axial direction is restricted.
In this way, displacement of the take-up shaft along the axial direction can be restricted even in a structure in which, for example, the interval between the pair of leg plates is shorter than the axial direction dimension of the take-up shaft and the take-up shaft is supported at the pair of leg plates indirectly by another connecting member or the like in the state in which the take-up shaft has been passed through holes formed coaxially in the pair of leg plates. Accordingly, the take-up shaft can be prevented from coming out from the holes, and it is possible to prevent an excessive load from being applied to the other connecting member due to displacement of the take-up shaft. Thus, the present webbing retractor can reliably be operated over a long period of time.
Moreover, the take-up shaft stopper device is structured so as to be mounted to the outer peripheral portion of the take-up shaft from a direction orthogonal to the axial direction of the take-up shaft. Thus, when the take-up shaft stopper device is mounted to the outer peripheral portion of the take-up shaft, the leg plates of the frame and the like do not interfere with the take-up shaft stopper device. In this way, basically, the take-up shaft stopper device can be mounted to the take-up shaft in a state in which the take-up shaft stopper device is set at a predetermined position of the take-up shaft with respect to the frame.
Thus, basically, because the take-up shaft stopper device can be mounted to the take-up shaft simply, the operational efficiency of the assembly work is extremely good.
Displacement of the take-up shaft along the axial direction is restricted due to the leg plates interfering with the take-up shaft stopper device. Thus, there is no longer the need to make the direction of assembling the take-up shaft to the frame complex, and no longer the need to restrict displacement of the take-up shaft along the axial direction. Namely, in the present webbing retractor, the direction of assembling the take-up shaft to the frame can be simplified, and the assembly efficiency can thereby be improved.
The webbing retractor of the present invention may be provided with a belt stopper device. A belt insert-through hole is formed in the take-up shaft, both ends of the belt insert-through hole are open at an outer peripheral portion of the take-up shaft, the proximal end side of the webbing belt is inserted through from one open end of the belt-insert through hole, and the take-up shaft stopper device is mounted from another open end of the belt-insert through hole. The belt stopper device is a device which engages the proximal end side of the webbing belt which has been inserted through the belt insert-through hole from the other open end of the belt insert-through hole, and which, in an engaged state, interferes one of directly and indirectly with an inner wall of the belt-insert through hole so as to prevent the webbing belt from coming out from the one open end of the belt insert-through hole, and which interferes with the take-up shaft stopper device from the other open end of the belt-insert through hole so as to prevent the take-up shaft stopper device from coming out from the other open end of the belt-insert through hole.
In the webbing retractor having the above-described structure, from the other open end of the belt insert-through hole, the belt stopper device engages with the proximal end side of the webbing belt which has been inserted through from the one open end of the belt insert-through hole formed in the take-up shaft. In this state, when the webbing belt is pulled toward the distal end side thereof, the inner wall of the belt insert-through hole interferes with the belt stopper device, and, via the belt stopper device, the proximal end side of the webbing belt is prevented from coming out from the one open end of the belt insert-through hole.
Here, in the present webbing retractor, the take-up shaft stopper device is mounted to the take-up shaft from the other open end of the belt insert-through hole. Moreover, in this mounted state, the belt stopper device, which engages with proximal end side of the webbing belt, interferes with the take-up shaft stopper device from the other open end of the belt insert-through hole. It is thereby possible to prevent the take-up shaft stopper device from coming out from the other open end of the belt insert-through hole.
In this way, in the present webbing retractor, the take-up shaft stopper device is mounted to the take-up shaft by the structure for anchoring the webbing belt to the take-up shaft, which structure is the belt insert-through hole and the belt stopper device. Thus, there is no need for a special structure for mounting the take-up shaft stopper device to the take-up shaft, and the costs can be made to be less expensive.
A webbing retractor of a second aspect of the present invention has a take-up shaft, a frame, a lock device and a stopper portion. The take-up shaft is a member on which a proximal end portion of an elongated, strip-shaped webbing belt is anchored, and takes-up the webbing belt from the proximal end side of the webbing belt by rotating in the take-up direction which is one direction around an axial center of the take-up shaft. The frame is a member which includes a pair of leg plates which are provided so as to oppose one another along an axial direction of the take-up shaft, an interval between the leg plates being shorter than a dimension between axial direction end portions of the take-up shaft, and a hole is formed in each of the leg plates, and the take-up shaft can be made to pass through the holes, and internal teeth are formed at an inner peripheral portion of at least one of the holes, and the frame indirectly supports the take-up shaft which has been passed through the holes. The lock device is a device which has a lock member, and which moves the lock member in directions of approaching and moving away from the inner peripheral portions of the holes under a predetermined condition. The lock member is a member which is provided at the take-up shaft so as to be movable in directions of approaching and moving away from the inner peripheral portions of the holes formed in the leg plates. A plurality of external teeth which can engage with the internal teeth are formed at the lock member. Due to the lock member moving so as to approach the inner peripheral portions of the holes, the lock member engages with the internal teeth formed at the inner peripheral portion of the hole, and restricts rotation of the take-up shaft in a direction of pulling-out the webbing belt. The stopper portion is provided at the take-up shaft so as to be movable in directions of approaching and moving away from a restricting position at a side, along a direction in which the leg plates oppose one another, of the leg plate which has the internal teeth, one of integrally with movement of and interlockingly with movement of the lock member in directions of approaching and moving away from the inner peripheral portions of the holes.
In the webbing retractor having the above-described structure, the proximal end portion of the elongated, strip-shaped webbing belt is anchored on the take-up shaft which is supported indirectly at the pair of leg plates of the frame. Due to the take-up shaft being rotated in the take-up direction which is one direction around the axis thereof, the webbing belt is taken-up and accommodated on the take-up shaft.
In this accommodated state, by rotating the take-up shaft in the pull-out direction which is opposite to the take-up direction by pulling the distal end side of the webbing belt, the webbing belt which is taken-up on the take-up shaft is pulled out. Due to a vehicle occupant making the webbing belt, which has been pulled out, span across his/her body at the front side of his/her body, the webbing belt is applied to the body of the vehicle occupant.
Under a predetermined condition such as when there is a rapid deceleration of the vehicle or when the webbing belt is pulled-out suddenly, the lock member which forms the lock device moves in the direction of approaching the internal teeth which are formed at the inner peripheral portion of at least one of the holes formed in the pair of leg plates, and the lock member engages with the internal teeth. In this way, rotation of the take-up shaft in the pull-out direction is restricted, and pulling-out of the webbing belt is thereby restricted.
Here, as described above, when the lock member moves in the direction of approaching the internal teeth, the restricting portion moves to the restricting position either integrally or interlockingly therewith. The restricting portion which has moved to the restricting position opposes, along the axial direction of the take-up shaft, the leg plate which has the internal teeth. Thus, in this state, if the take-up shaft attempts to shift in the axial direction, the leg plate which has the internal teeth interferes with the stopper portion, and the take-up shaft is interfered with via the stopper portion. As a result, displacement of the take-up shaft along the axial direction at the time the lock member moves (i.e., under the aforementioned predetermined condition) is restricted.
In this way, the take-up shaft can be prevented from coming out from the holes in which the internal teeth are formed, and it is possible to prevent an excessive load from being applied to another connecting member due to displacement of the take-up shaft. Thus, the present webbing retractor can reliably be operated over a long period of time.
When the webbing retractor includes the stopper portion, the stopper portion may be formed between the plurality of external teeth.
In the webbing device having the above-described structure, the stopper portion is formed between the plurality of external teeth formed at the lock member. Accordingly, when the lock member moves to approach the internal teeth and the external teeth engage with the internal teeth, the stopper portion is positioned at the side of the internal teeth along the axial direction of the take-up shaft. In this state, if the take-up shaft attempts to shift along the axial direction, the internal teeth interfere with the stopper portion, and, via the stopper portion and the lock member, the internal teeth interfere with the take-up shaft at which the lock member is provided. In this way, displacement of the take-up shaft along the axial direction is restricted.
A third aspect of the present invention relates to a method of assembling a webbing retractor. This method is applied to a webbing retractor having: a take-up shaft on which a proximal end portion of an elongated, strip-shaped webbing belt is anchored; and a frame having a pair of leg plates which oppose one another along an axial direction of the take-up shaft, and an interval between the leg plates is smaller than an axial direction dimension of the take-up shaft, and a hole through which the take-up shaft can pass is formed in each of the leg plates, and the frame indirectly shaft-supports the take-up shaft at the pair of leg plates. This method has a step of mounting the take-up shaft to the frame. The step of mounting the take-up shaft to the frame comprises the following two steps. The first step is a take-up shaft pass-through step of passing the take-up shaft, from one axial direction end side of the take-up shaft and along the axial direction of the take-up shaft, through the hole formed in one of the leg plates, from a side of the one of the leg plates which side is opposite a side at which another of the leg plates is provided, and passing the take-up shaft, from the one axial direction end side of the take-up shaft, through the hole formed in the other of the leg plates. The second step is a take-up shaft stopper device mounting step of mounting a take-up shaft stopper device to one portion of an outer periphery of the take-up shaft, between the pair of leg plates and from a direction orthogonal to the axial direction of the take-up shaft, and making a restricting wall, which is formed at the take-up shaft stopper device and extends further toward an outer side in a direction orthogonal to the axial direction of the take-up shaft than the take-up shaft, oppose the leg plates along the axial direction of the take-up shaft.
In the above-described method of assembling a webbing retractor, when the take-up shaft is mounted to the frame, first, in the take-up shaft pass-through step, the take-up shaft is passed, from the axial direction one end side of the take-up shaft and along the axial direction of the take-up shaft, through the hole formed in one of the leg plates forming the frame, from a side of the one of the leg plates which side is opposite the side at which the other leg plate is provided. Then, the take-up shaft is passed, from the one axial direction end side thereof, through the hole formed in the other leg plate.
Next, in the take-up shaft stopper device mounting step, the take-up shaft stopper device is mounted to one portion of an outer periphery of the take-up shaft, between the pair of leg plates and from a direction orthogonal to the axial direction of the take-up shaft.
In this state in which the take-up shaft stopper device is mounted, the restricting wall formed at the take-up shaft stopper device extends further than the take-up shaft toward an outer side in a direction orthogonal to the axial direction of the take-up shaft, and opposes the leg plates along the axial direction of the take-up shaft. Accordingly, if the take-up shaft attempts to shift along the axial direction, the leg plates interfere with the restricting wall, and the leg plates interfere with the take-up shaft indirectly via the restricting wall (the take-up shaft stopper device). In this way, displacement of the take-up shaft along the axial direction is restricted, and the take-up shaft can be prevented from coming out via the holes.
Here, in the present method for assembling a webbing retractor, as described above, by mounting the take-up shaft stopper device to the take-up shaft in the take-up shaft stopper device mounting step, displacement of the take-up shaft along the axial direction is restricted. Thus, when positioning the take-up shaft at a predetermined position of the frame, the take-up shaft passthrough step, which passes the take-up shaft through the holes formed in the leg plates along the axial direction of the take-up shaft, alone suffices.
In this way, in the present method for assembling a webbing retractor, the mounting of the take-up shaft to the frame is simple. Therefore, assembly is easy, and it is possible to reduce the number of assembly steps.